1. Field of the Invention
The present invention generally relates to the decoding of commands, and more particularly to a command decoding system, a flash memory command decoding system, a method of decoding a command, and a method of decoding a flash memory command.
2. Description of the Related Art
In addition to a main processor, electronic devices such as computer systems and cellular phones also include various peripheral devices such as a display device, a keyboard, and a memory. The main processor transmits commands to the peripheral devices to control the peripheral devices.
Generally, each of the peripheral devices includes a device controller for executing a transmitted command from the main processor, and executes at least one micro-command corresponding to the transmitted command so as to process the transmitted command from the main processor.
For example, in the case of a flash memory controller of a flash memory, when the main processor provides a read command for reading data stored in a specific address to the flash memory controller, the flash memory controller sequentially executes micro-commands corresponding to the read command so as to execute the read command, and provides the data stored in the specific address to the main processor.
An operation in which the device controller executes the micro-commands may be in accordance with two different methods.
A first method is where the device controller directly receives the micro-commands from the main processor. Here, the device controller includes a register directly accessible by the main processor, and executes the micro-commands received from the main processor. In this first method, an operational speed is disadvantageously decreased since the main processor has to directly transmit data to the device controller.
A second method is where the device controller includes a micro-command table used for storing the micro-commands and executes the micro-commands corresponding to the command by using the micro-command table. Here, the device controller decodes a command received from the main processor, searches the micro-commands corresponding to the decoded command for the micro-command table and executes the searched micro-commands. In the second method, the micro-command table is generated when the device controller is manufactured, and the generated micro-command table is not changed after the device controller is manufactured. Therefore, the device controller is unable to add new micro-commands and executes only pre-defined micro-commands.